1. Field of the Invention
The present invention generally relates to a camera, and particularly relates to the camera which can perform a viewfinder and monitor display.
2.Description of the Related Art
Conventionally, there have been proposed a video camera and a digital still camera, in which both of a viewfinder display and a monitor display can be performed or made.
FIG. 1 is a block diagram showing a general construction of a conventional digital still camera. As shown in the figure, a lens barrel unit 1, a CCD image taking element 2, an LCD (i.e. Liquid Crystal Display) 4 for an EVF (i.e. electronic viewfinder), an LCD 5 for a monitor on a rear side, a circuit 7, including both of an electric power supply circuit and a flash circuit, which is electrically connected to a flash emitter 6 and a battery 8, and the battery 8, are electrically connected to a main substrate (or main board) 3. The main substrate 3 has a CPU 3a, a memory 3b, a camera control circuit 3c, an external terminal (or an interface circuit) 3d, and a pair of IC 3s and 3t for electrically driving the pair of LCD units 4 and 5, respectively.
In a case of mounting such a pair of LCDs 4 and 5, and mounting such a pair of ICs 3s and 3t, the construction leads to a high cost of camera. Therefore, in order to prevent this high cost, it is possible to take into consideration that the display device for the monitor display is also employed as the display device for the viewfinder display.
For example, Japanese Laid-Open Patent Publication No. 11-265023, Japanese Laid-Open Patent Publication No. 8-130665, and Japanese Laid-Open Patent Publication No. 9-18754, disclose a type of camera and a type of viewfinder device, in which a display device rotates outside its housing. According to the construction thereof, when the display device opens relative to the housing thereof, the user can directly view the image plane (or picture plane) of the display device. On the other hand, when the display device closes relative thereto, the user can observe the image plane of the display device through its optical system provided inside the housing.
On the other hand, Japanese Laid-Open Patent Publication No. 2001-268404 discloses a type of camera in which a display device is fixed to the housing thereof. In the construction thereof, a prism has a semi-transmission optical surface, by which a flux of light (or luminous flux or beam of light) from the image plane of the display device is separated into two fluxes of light, one of which is for the monitor display and the other of which is for the viewfinder display.
According to the construction disclosed in each of Japanese Laid-Open Patent Publication No. 11-265023, Japanese Laid-Open Patent Publication No. 8-130665, and Japanese Laid-Open Patent Publication No. 9-18754, however, it is necessary to keep or set aside a particular space which is occupied only by the optical system. Therefore, with the construction, it is difficult to make the apparatus smaller or more compact.
Meanwhile, according to the construction disclosed in Japanese Laid-Open Patent Publication No. 2001-268404, the prism also occupies a predetermined space for itself. Therefore, with the construction, it is also difficult to make the camera smaller or more compact. In addition, because of the prism, the camera having the prism becomes heavier, and the manufacturing cost is higher. In addition, because of the semi-transmission optical surface, its luminance (or brightness) is lower.